酒石酸法合成的LiCoO_2的结构及其二次锂电池行为研究

Studies on the Structure of LiCoO_2 Synthesized with Tartaric Acid and the Behaviorof its Rechargeable Lithium Battery

采用Ｘ射线衍射，光电子能谱，库仑滴定，循环伏安等方法研究酒石酸法合成的ＬｉＣｏＯ＿２的结构及其二次锂电池行为。结果表明ＬｉＣｏＯ＿２具有六方晶系空间群结构，相应晶胞参数ａ＝０．２８１０ｎｍ，ｃ＝１．４０８８ｎｍ；其中Ｃｏ￣（３＋）为低自旋；且其表面存在Ｌｉ＿２Ｏ。同时，其二次锂电池电容量可达１２０ｍＡ·ｈ·ｇ￣（－１），半容量工作电压达３．８ｖ，当正极中Ｌｉ￣＋含量（Ｘ）为０．４５１≤ｘ≤０．９３４时，该电池开路电压（Ｅ）符合：Ｅ＝４．３１８－０．４５０Ｘ￣（２／３）。

The structure of LiCoO_2 synthesized with tartaric acid and the behavior of itsrechargeable Lithium battery have been studied by XRD, XPS, CV. CT. It has been shown thatLiCoO_2 has a space group R3m with hexagonal parameters a=0.281 0 nm,c=1.408 8 nm. Low-spin state Co￣(3+) configuration in LiCoO_2 has been suggested. Also,Li_2O, was identified onits surface.Furthermore, the capacity and the middle working voltage of its Lithium battery are about 120 mA·h·g￣(-1) and 3.8 V,respectively.The EMF of the cell changes with the Lithium composition of itscathode following E=4.318-0.450 X￣(2/3) in 0.451≤X≤0.934.